The energy spectrum of ultra-high energy cosmic rays measured at the Pierre Auger Observatory and the Telescope Array oleh Bergman D. R., Deligny O., Fenu F., Fujii T., Fujita K., Kim J. H., Lhenry-Yvon I., Maris¸ I., Luce Q., Roth M., Salamida F., Tsunesada Y., Verzi V.